Jeff,

Here is the baseline I am using.

Create a new profile using Makerbot PLA for Z18 Standard.

Setting I change in this created profile.

Layer Height - I will modify this from 0.15 to 0.25 depending on the model
DoDynamicSpeed - true (this will slow the speed at tight corners leaving less pull away)
ExtruderTemp - default is 215, you can vary this to what works good for you but in my shop and the room temp it works best for most of the PLA I have at around 220)
ChamberTemp - 35C
Number of Shells - 4
Infill Density - 0.03 - 0.05 (if your printing small objects you may want to run 0.10 - 0.15)
Extrusion Profile - Change the speeds here, these are working constantly for me, doesn't mean you can't adjust to fit your needs.
Bridge Feedrate - 40
FirstLayer - 30
FirstLayerRaft - 50
Infill - 40
Insets - 40
Outlines - 20
RaftBase - 10

Drop on over to Bold Machines to see what they are doing with the Z18's. They have 10 Z18's running 24/7. They run most things over there at 0.30 using the default Fast Settings from the control panel due to the size parts they are printing. http://www.boldmachines.com/